Ultra-thin MoO2 nanosheets loaded on hollow mesoporous carbon spheres promoting polysulfide adsorption and redox kinetics for lithium-sulfur batteries

Abstract

Inhibiting polysulfide shuttle and improving cycling stability are crucial for the commercialization of lithium-sulfur batteries (LSBs). Developing multifunctional sulfur host materials that combine rational carbon structure with highly catalytic metal compounds is pivotal for LSBs. Herein, Ultra-thin MoO2 nanosheets loaded on hollow mesoporous carbon (HMC@MoO2) were rationally designed and synthesized. In this structure, the hollow mesoporous carbon provides sufficient space to store sulfur and buffer volume fluctuations, the mesoporous carbon shell and the MoO2 nanosheets on its surface can act as a double defensive system to effectively prevent polysulfide dissolution through physical and chemical trapping. Moreover, the ultra-thin MnO2 nanosheets with more exposed active sites facilitate the capture and catalytic conversion of LiPSs, thereby effectively suppressing the shuttle effect of polysulfide. Consequently, the HMC@MoO2-S cathode exhibits impressive cycling stability, maintaining 771 mAh g−1 after 500 cycles at 0.5 C with a very low capacity decay of 0.045% per cycle. In particular, the HMC@MoO2-S cathode with high areal sulfur loading of 5.0 mg cm−2 achieved initial areal capacities of 4.48 mAh cm−2 and retention capacities of 3.32 mAh cm−2 after 500 cycles at 0.1 C.